Belt drive kit and module

ABSTRACT

A belt drive kit comprising a driver sprocket, a driven sprocket, an idler, a belt tensioning device and a toothed belt and fasteners for attaching the components to an engine.

FIELD OF THE INVENTION

The invention relates to a belt drive kit and module, namely, a kit comprising components for use in a belt driven camshaft system and preassembled module for fitment to an engine.

BACKGROUND OF THE INVENTION

Engine assembly generally comprises combining the component parts in a predetermined sequence. To accomplish the assembly the parts must be made available to the engine builder. This comprises sourcing and taking delivery of various system parts from a variety of manufacturers. The system parts are inventoried and stored. When the sequence requires a certain part to be assembled to the engine the part is retrieved from inventory, made available to the engine builder who then affixes it to the engine build.

Components may be obtained from a single source or from a variety of sources. Tracking and sequencing the various components involves labor time and facilities for handling the components. Further, the absence of a single component can stop the assembly process even though all other components are readily available. This also applies to maintenance activities were parts are replaced in addition to the part of primary interest because it is simply financially prudent to replace a series of low cost parts based on the time and cost required to access the part to be maintained.

Kits are known for retrofitting existing engines with systems differing from those originally installed on the engine.

Representative of the art 5,460,145 (1995) to Perry, Jr. which discloses a kit for a motorcycle supercharger drive assembly.

What is needed is a belt drive kit comprising a driver sprocket, a driven sprocket, an idler, a belt tensioning device, a toothed belt and fasteners for attaching the components to an engine. What is needed is a preassembled module comprising the kit components for fitment to an engine. The present invention meets these needs.

SUMMARY OF THE INVENTION

The primary aspect of the invention is to provide a belt drive kit comprising a driver sprocket, a driven sprocket, an idler, a belt tensioning device and a toothed belt and fasteners for attaching the components to an engine.

Another aspect of the invention is to provide a preassembled module comprising the kit components for fitment to an engine.

Other aspects of the invention will be pointed out or made obvious by the following description of the invention and the accompanying drawings.

The invention comprises a belt drive kit comprising a driver sprocket, a driven sprocket, an idler, a belt tensioning device and a toothed belt and fasteners for attaching the components to an engine.

BRIEF DESCRIPTION OF THE DRAWINGS

The accompanying drawings, which are incorporated in and form a part of the specification, illustrate preferred embodiments of the present invention, and together with a description, serve to explain the principles of the invention.

FIG. 1 is a plan view of the synchronous drive kit.

FIG. 2 is a perspective partially exploded view of the kit.

FIG. 3 is a top view of a module.

FIG. 4 is a perspective view of the module.

FIG. 5 is a front view of the module.

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENT

The invention comprises a belt drive kit and module. The kit comprises components of a camshaft synchronous belt drive system for use on an internal combustion engine, for example, on a motorcycle engine. The module comprises the kit components assembled on a frame, which frame is then attached to an engine during engine assembly.

FIG. 1 is a plan view of the kit. The kit comprises valvetrain timing components that would be used by an engine assembler or mechanic for initial engine assembly or for repair of an engine. The components generally comprise a camshaft belt drive system.

In operation the system is used to transfer torque from a driver such as an engine crankshaft through a flexible endless member, i.e. a toothed (synchronous) belt, to sprockets on one or more engine camshafts. The engine camshafts comprise lobes which actuate the engine exhaust and inlet valves in a manner known in the art. The kit further comprises components used for properly setting and maintaining belt routing (idler pulleys); for belt preload and tension (belt tensioning device); as well as for fastening the sprockets, idlers and belt tensioning components to the engine or frame. The kit conveniently makes available to a user all of the necessary belt drive camshaft timing components. As noted the components may be connected to an engine during engine assembly, or, they may be connected to a module frame and the frame is then fitted to an engine during final engine assembly.

The kit comprises a number of components, including a crankshaft sprocket 5. Crankshaft sprocket 5, or driver member, is toothed for the purpose of engaging a belt. Sprocket 5 is mountable to an engine crankshaft (i.e. a driver shaft), see FIG. 2. Crankshaft sprocket 5 comprises either metallic material, including steel or aluminum, or non-metallic material, including urethane or resin. The sprocket may be spun formed using methods known in the art.

Crankshaft sprocket 5 comprises a crank position wheel 7. Crankshaft position wheel 7 provides a reference detent 7 a. Detent 7 a can be used for determining the position of the engine pistons as well as providing a reference signal generator for use by an electronic ignition pick up, see FIG. 5. Piston position is an important element of properly timing an engine. The detent trips a pick up sensor causing the electronic ignition to fire a spark plug.

Crankshaft sprocket 5 also comprises a flange 6. Flange 6 is used to keep belt 15 entrained on the crankshaft sprocket 5 by limiting lateral movement of the belt.

The kit also comprises camshaft sprockets 2. Each camshaft sprocket 2, or driven member, is toothed. Each camshaft sprocket 2 is connected by a fastener 4 to an end of an engine camshaft (driven shaft). Fasteners 4 in the present embodiment comprise nuts known in the mechanical arts. Fasteners 4 may also comprise bolts. This embodiment comprises three camshaft sprockets 2, and therefore accommodates a three camshaft engine. The camshafts are used to actuate inlet and exhaust valves on the engine in a form and manner known in the art, see FIG. 3. Camshaft sprockets 2 comprise either metallic material, including steel or aluminum, or non-metallic material, including urethane or resin. Each camshaft sprocket may also be spun formed using methods known in the art.

The kit also comprises idlers. Idlers 8, also referred to as pulleys or idler pulleys, are used to maintain the proper predetermined routing of belt 15. Idlers 8 are shown as “back-side” idlers since they engage the side of the belt opposite the toothed side. Synchronous belt 15 is entrained between the crankshaft sprocket 5 and camshaft sprockets 2. Synchronous belt 15 comprises teeth 15 a which engage cooperating grooves 15 b on each of the camshaft sprockets 2 in a manner known in the art. Crankshaft sprocket 5 also comprises teeth and grooves for engaging belt 15.

The toothed engagement between belt 15 and sprocket 5 and sprockets 2 maintains the proper timing relationship between crankshaft (and thereby the pistons), and the camshafts (and thereby the inlet and exhaust valves). Teeth 15 a further comprise a profile which allows belt 15 to efficiently transmit torque from the crankshaft sprocket 5 to the camshaft sprockets 2.

The kit also comprises a belt tensioning device or tensioner. Tensioner 1 is disposed between the crankshaft sprocket 5 and a camshaft sprocket 2. Tensioner 1 comprises an eccentric arm type tensioner known in the art. For example, and not by way of limitation, an eccentric type tensioner disclosed in U.S. Pat. No. 5,256,112, incorporated herein by reference, may be used.

Tensioner 1 is used to maintain proper belt preload and operating tension thereby preventing the belt from ratcheting, that is, skipping teeth with respect to the sprocket in the direction of movement, or otherwise disengaging from the sprocket by lateral movement.

The kit is contained in a box 16, or package, for containing the kit components as well as for shipping to an assembly location. The components may be restrained during shipping in box 16 by use of a molded plastic insert 16 a. Insert means 16 a comprises receiving portions dedicated to receiving and organizing each of the described components in predetermined positions for ease of shipping and use.

The kit may also comprise an instruction manual 16 b, in written or electronic form for example CD, used to explain installation of the kit components on an engine. The instruction manual may include torque values for attaching each sprocket to the respective camshaft or crankshaft; torque values for attaching each idler to a mounting surface such as an engine crankcase; torque values for attaching the tensioner to a mounting surface such as a crankcase; the proper method of installing and loading the tensioner for setting a belt preload; the proper method of setting the position of the timing wheel 7 with respect to an engine piston position; the proper method of attaching each camshaft sprocket to each camshaft for proper valve timing; and the proper method of installing the belt on the sprockets and idlers, including proper belt routing. The instruction manual may contain any further information deemed relevant to the installation and operation of the kit, its components and the engine on which it is installed.

FIG. 2 is a perspective partially exploded view of the kit. In this embodiment, the idlers each comprise a fastener bolt 14, washer 13, shaft 12, snap ring 11, bearing 10, washer 9 and idler pulley 8 in stacked relation to each other as shown. Each of the foregoing components is known in the art. When the idler is installed on a mounting surface, bolt 14 is simply torqued into a receiving hole on a cam timing cover or other crankcase mounting surface as may be required by the engine design and in accordance with the torque rating for bolt 14.

With respect to each of the camshaft sprockets 2, fastener nut 4 and washer 3 are used to attach the sprocket 2 to a respective camshaft (not shown) . The noted parts are assembled on an engine by nut 4 and washer 3 being torqued on each respective camshaft, see FIG. 3. The camshaft end comprises a threaded portion to engage the nut. The camshaft sprocket may be aligned with the camshaft by use of keyways, pins, splines and the like.

With respect to the crankshaft sprocket 5, nut 4 and flange 6 are used to attach sprocket 5 to the engine crankshaft. Crankshaft position wheel 7 is disposed between the crankshaft and the crankshaft sprocket 5. The noted parts are assembled on an engine by nut 4 and washer 3 being torqued on the crankshaft (not shown). Crankshaft sprocket 5 and wheel 7 may be aligned with the crankshaft by use of keyways, pins, splines, and the like. Teeth 5 a are shown on sprocket 5.

FIG. 3 is a top view of a module. This view depicts a complete module ready for installation on an engine, as opposed to FIGS. 1 and 2 which show the kit components in a box. Namely, the kit components described in FIGS. 1 and 2 are assembled on a module frame 100 which is then permanently installed on an engine.

Module frame 100 is an engine component which is a permanent part of the engine into which it is installed. More particularly, frame 100 is attachable to an engine crankcase 300, the engine crankcase having a shape suitable for receiving frame 100.

Crankcase 300 is shown in partial schematic form since its shape is ultimately determined by the particular engine. Hence, the particular crankcase form is not specifically described since the frame can be shaped to accommodate any engine crankcase style or shape.

Portion 200 comprises a structural member of frame 100. Bolts 201 fasten portion 200 to an engine crankcase. The shape or need for portion 200 is determined by the shape of the particular engine to which frame 100 is mounted.

The engine crankcase and related components may comprise a crankshaft, connecting rods, pushrods, valves, cylinders, pistons heads, and so on. Frame 100 is fastened to the crankcase in a manner which properly disposes the camshafts in operational relation to the valve pushrods and/or rocker arms. Frame 100 also mounts in predetermined relation to the crankshaft for proper fitment of the crankshaft sprocket 5 and timing wheel 7. Sprocket 5 and timing wheel 7 are connected to the crankshaft when frame 100 is fastened to the crankcase. Frame 100 also serves to seal the internals of the crankcase to allow proper oil circulation, see FIG. 4 which depicts gasket 35 used for this purpose. Frame 100 may be cast, sintered or machined from known metal stocks, such as aluminum, magnesium or steel or combinations of two or more thereof.

Camshafts 70, 80, and 90 are installed in their respective races on the side of frame 100 opposite sprockets 2. In this embodiment bolts 14 are used in lieu of nuts 4 to secure sprockets 2 to each of the camshafts 70, 80, 90.

Camshafts 70, 80, 90 may be included in the kit, or, may be included with the engine. Camshafts 70, 80, 90 also engage bearing races (not shown) in the engine crankcase that are disposed opposite frame 100 in accord with the engine design.

Each camshaft 70, 80, 90 engages a respective bearing 70 a, 80 a, 90 a. Each bearing is engaged with a receiving socket in frame 100. As part of assembly of the module, each camshaft and thereby cam lobe 70 b, 80 b, 90 b is rotationally oriented with respect to the other camshafts for the purpose of properly timing inlet and exhaust valve operation when the module is assembled in an engine crankcase. Pin 36 is used to properly align frame 100 with an engine crankcase.

FIG. 4 is a perspective view of the module. Each of the components described in FIG. 1 are assembled on the module frame 100. Before final assembly of the frame to the engine, the idler pulley 8 and the belt tensioning device 1 are attached to frame 100. Toothed belt 15 is temporarily loosely engaged with the driver sprocket 5, the driven sprockets 2, the idler pulley 8 and the belt tensioning device 1 as described herein.

Camshafts 70, 80, 90 are each inserted into its respective bearing, which is then inserted into the respective frame receiving socket. Sprockets 2 are secured to each camshaft by bolts 14. Idlers 8 are secured to the frame 100 by bolts 14. Tensioner 1 is secured to frame 100 by bolt 1 a. The tensioner is locked in a preload position using a pin or other means known in the art. Belt 15 is routed on the sprockets, idlers and tensioner. Once the belt is properly routed, the tensioner is released from the preloaded position to properly engage and thereby preload the belt. The tensioner may be released upon assembly of the module, or, upon assembly of the module to the crankcase. Gasket 35 seals frame 100 with the engine crankcase.

Crankshaft sprocket 5 is secured to the crankshaft 400 using bolt 14 engaged at threaded hole 401 when the module is attached to the engine crankcase. For installation it is necessary that the engine crankshaft be already installed in the engine crankcase in order to receive sprocket 5 and bolt 14.

In this FIG. 4 a bolt 14 is described. Referring to FIG. 1 a nut 4 is also described. Either a nut 4 or bolt 14 may be used to fasten sprocket 5 to crankshaft 400 with equal success. This is also the case with respect to sprockets 2, which may be fastened with a nut 4 as described in FIG. 1, or with a bolt 14 as described in FIG. 4.

FIG. 5 is a front view of the module. Ignition timing sensor 45 is aligned with the timing wheel 7. Connector 44 is included in an engine wiring harness (not shown). Once frame 100 is fastened to the engine, connector 44 is connected to the wiring harness. Frame 100 is fastened to the engine using bolts (not shown) that are engaged through holes 101.

Although forms of the invention have been described herein, it will be obvious to those skilled in the art that variations may be made in the process and construction and relation of parts without departing from the spirit and scope of the invention described herein. 

1. A belt drive kit comprising: a driver member; a driven member; a belt tensioning device; a fastener for attaching the driver member to a first engine component; a fastener for attaching the driven member to a second engine component; a fastener for attaching the belt tensioning device to a mounting surface; and a toothed belt.
 2. The kit as in claim 1 further comprising a pulley and a fastener for rotationally attaching the pulley to a mounting surface.
 3. The kit as in claim 1 further comprising instructions for assembling the kit on an engine.
 4. The kit as in claim 1, wherein the first engine component comprises a crankshaft.
 5. The kit as in claim 1, wherein the second engine component comprises a camshaft.
 6. The kit as in claim 1 further comprising a timing member engaged to the driver member, the timing member comprising a detent for indicating a piston position.
 7. The kit as in claim 1 further comprising a flange attached to the driver member.
 8. The kit as in claim 1 further comprising an instruction manual.
 9. The kit as in claim 1, wherein the driven member comprises urethane.
 10. The kit as in claim 1, wherein the driver member comprises teeth.
 11. The kit as in claim 1, wherein the driven member comprises teeth.
 12. The kit as in claim 1, wherein the belt tensioning device comprises an eccentric arm tensioner.
 13. The kit as in claim 1 further comprising a package for containing the kit components.
 14. The kit as in claim 13 further comprising insert means for retaining the components in predetermined positions.
 15. A belt drive module comprising: a driver member attachable to a driver shaft; a driven member attachable to a driven shaft; an idler pulley; a belt tensioning device; a toothed belt; a frame for receiving the driver shaft and the driven shaft; the idler pulley and the belt tensioning device attached to the frame; and the toothed belt engaged with the driver member, the driven member, the idler pulley and the belt tensioning device.
 16. The belt drive module as in claim 15, wherein the driver member and the driven member have a toothed profile.
 17. The belt drive module as in claim 15, wherein the belt tensioning device is an eccentric tensioner.
 18. The belt drive module as in claim 15, wherein the frame is connectable to an engine crankcase.
 19. The belt drive module as in claim 15, wherein the driver shaft comprises a crankshaft.
 20. The belt drive module as in claim 15, wherein the driven shaft comprises a camshaft. 